From DE 196 46 698 A1, a side airbag device is known with a thorax section and a separate head section. It is proposed here, on the one hand, that the thorax chamber and the head chamber are filled by separate gas generators, and on the other hand, that the thorax chamber is filled directly via a gas generator, and an overflow opening is provided, by means of which the thorax chamber fills the head chamber with gas.
It has been shown that when a safety belt is present, whose upper deviation point is not located on the armrest, but rather on the interior structure of the vehicle, i.e. usually on the B-pillar, the problem can occur, at least in some seat positions, that the expanding head section comes into contact with the safety belt, which obstructs the head section's expansion and reduces the desired protective effect, at least to some extent.
From the category-defining U.S. Pat. No. 6,425,602 B1, a vehicle seat with a side airbag device is known that has a thorax section and two head sections. The thorax section and the head section, which are arranged on the same side of the vehicle, are laterally offset, so that there is an empty space between them. The thorax section and the two head sections are separate airbags that are supplied with gas, if needed, by a compressed gas line. The system described is mechanically very complicated and relatively heavy.
DE 196 26 761 C1 shows a vehicle seat with a side airbag device, the side airbag device having a thorax section and a head section. Here too, the thorax section and the head section are designed as completely separate airbags that are connected via a compressed gas supply line. Here the head section is arranged in the headrest.
U.S. Pat. No. 5,615,909 shows a vehicle seat with a head airbag, which is arranged in an upper region of the backrest beside the headrest.